1. Field of the Invention
The present invention relates generally to the field of apparatuses for converting energy from flowing fluid into electricity or another power type. Moreover, it pertains specifically to a modular, extensible apparatus and system for converting wind, water or other fluid energy into electricity or another form of mechanical energy. Accordingly, the present invention provides a solution to the shortcomings of prior wind turbine systems, apparatuses, and methods, especially for low speed or urban winds.
2. Description of the Related Art
Alternative energy or renewable energy solutions and technologies have been explored including wind and solar for many decades. Yet, there is a huge untapped market for these energy creation devices. The challenge of finite natural resources (fossil fuels, oil and coal) is not limited to the United States. All countries are faced with this same problem giving rise to a worldwide need for economical, easy to use alternative energy products.
According to the World Energy Association, “The availability of wind power in the atmosphere is five times greater than the world's current energy consumption in all forms per year; yet wind energy currently produces approximately 1% of the world's electricity use.”
To achieve a universal business and residential use device, it must not only be economical, but also must be aesthetically pleasing, highly efficient and easy to install.
A mass-produced renewable energy solution for residential and urban applications would be beneficial to all. However, creating devices economically which take advantage of “small winds” (known in the industry as Class 1, 2, 3) in a meaningful way is a great challenge. One problem is that existing generators have a moment of inertia to overcome to begin generating electricity and small winds are typically insufficient to overcome this state of rest. Moreover, urban and suburban residential and commercial buildings often have strict codes to adhere to, and face practical limitations on the use of wind-power. Wind turbines can be huge, and the dynamic forces of a spinning turbine are great. Use of such turbines in urban areas is dangerous.
Further, the industry has taught that wind with disruption, i.e., turbulent flow around structures and near the ground (in the “boundary layer”) is not useful or desirable. Accordingly, wind energy devices have been relegated to rural areas. For example, in rural areas, there is sufficient room to build strong towers to hold the turbines up high with no structures in the surrounding area which allows wind forces to flow without significant disruption (laminar flow).
These alternative energy solutions have traditionally been focused on large or utility scale applications such as: removing the need for external sources of energy for a home or office and using a system of net metering, selling unused energy back to the utility company and/or feeding the energy directly into the public utility grid. Even a scaled down version of a wind turbine can be tens of feet in diameter. Each of these cases ignores the vast amount of available energy in urban settings.
According to an article dated Feb. 10, 2009 posted at News.cnet.com entitled “Study delivers blow to urban microwind turbines”, by Martin LaMonica, Southwest Wind Power, which makes a small wind pole-mounted turbine, suggests minimum requirements for installation which include a ten mile-per-hour average wind and a twenty foot clearance above any obstructions. Another article (entitled “Study: Microwind turbines a tough sell in Mass.”) dated Mar. 17, 2009 by the same author at the same web site, teaches that even small turbines must be well above obstructions to get useful output.
Wind speed seen by the turbine varies with the turbine's height above ground and any obstructions near the turbine. Trees, shrubs, buildings and other obstructions retard the flow of the wind. Each doubling of height of the turbine arguably increases the power available by ten percent. So the industry teaches increasing the height of the turbine to increase available wind power by about two times, such as taught by Paul Gipe, author of Wind Energy Come of Age.
In spite of the art teaching that it is not practical, what is needed is a way to take advantage of small winds, in a cost effective and energy efficient way.